Pop-up structures are well known, and typical known pop-up structures are shown in the following listed patent documents: U.S. Pat. No. 5,346,455 granted Sep. 13, 1994; 4,146,983 granted Apr. 13, 1979; 5,181,901 granted Jan. 26, 1993; and published application PCT/US96/04360. Typical pop-up structures are shown in U.S. Pat. No. 5,582,888 in FIGS. 29, 34, 45, and 72. These structures are intended to be used with a pair of hinged panels, and have integral supporting structures or "legs" extending from the main display area of the pop-up structures, with these supporting structures or legs being secured to both of the two hinged panels, so that when the hinged panels are unfolded, the main display area "pops up" from the panels.